Lifting-jack.



L. ATWELL.

LIFTING JACK. APPILICATION FILED APR. 28. i916. Patented Oct. 23, I

3 SHEETS-SHEET 1. v 3: PB 3 F Jun 7. avmmmtoz iiia 42% @511 g fieQ atbomm L. ATWELL.

LIFTING JACK. APPLICATION FILED APR. 2a. 1916.

Patented 00$. 23, 1917.

3 SHEETS-SHEET 2.

4 a \Q X g a W M r E i 6 6 E 6 7 on 7 E E an 7\ I a m F E a FFTQE.

rocxnhrwntr, or sari/In, ALABAMA.

LIFTING JACK.

Twill whom itmay concern: r

130- it known thatLLoonn A'rwEL a citizen of the United States, residing at Selma, in the county of Dallas and State of Alabama, have invented a new and useful Improvement Lifting-Jacks, of which the following is a specification, reference being had to the accompanying drawing.

My improvement relates particularly to lifting jacks comprising a base section and a plunger or head section and a screw arranged in operative relation with said sections for driving them endwise relative to each other and mechanism for turning said screw, said mechanism comprising ratchet members operated by hand lever.

The purpose of my invention is to. automatically put said ratchet mechanism out of action when the screw has movedthe plunger through a chosen distance while lifting a load. Q dlvhile the screw is" being turned for lifting a load,'it is desirable that the screwbenotturned so far as to disengage altogether from the plunger nor even so far as toleave only a small number of turns of the thread in engagement with the plunger, for it has repeatedly been shown in practice that under such condition the weight of the load is apt to strip the threads and allow the hoisted body to fall and further damage the lifting jack and to injure the workmen. In this connection,

it is to be observed that my improvement is intended to be applicable specially to lift,- ing jacks used for lifting railway cars and other heavy bodies ranging from twentyfive tons to one hundred tons or more.

7 Efforts have heretofore been made to prevent excessive lifting of the plunger, such efiorts being directed to applying means for indicating to the eye or the ear when the screw has turned to the danger limit. But such means, have left it possible for the operator to disregard, intentionally or unintentionally, the indication. In my improved structure, the members of the ratchet mechanism become automatically disengagedfrom each other when thechosen movement of the plunger has'been attained, so thatturning of the screw ceases, although the operator continues to oscillate the hand lever.

In the accompanying drawings,

Figure a side elevation of a lifting Specification of Letters Patent.

Patented Oct. 23, 1917.

Application filed April 28, 19l6. Serial No. 9;,138.

jack embodyinginy improvement, portions being broken away; i w n I f I Fig. 2 is a sectional elevation looking at the apparatus from theright as shown Fig. 1';v I i I Fig. 3 is a section on the line, 3-3, of Fig. 2, lookingtoward theright;

Fig. 4 is a horizontal section on the line, 4--l, ofFigs. 1 and 2;

Fig. 5 is a section on the line, 55, of Fig. 2, looking toward the right;

Fig. 6 is a section on the line, 6-6, of Fig. i, looking toward the left;'

Fig. is a section on the upper portion of a plane which is perpendicular to Fig. 2 and cuts said figure along its upright axis, the view being toward the left Fig. 8 is an elevation of the connecting bar shown detached and in the position occupied in Fig. 2;

Fig. 9 is a horizontal section on the line, 99, of Fig. 8; i

Fig. 10 is a rear elevation of the pawl detached from the other mechanism;

Fig. 11 is a section on the line, 11-11, of Figs. 1 and t, looking in the direction of thearrow.

Referring to said drawings, A is the base and B is theplunger. .Said base and said plunger are made telescoping in the usual manner. Either of these memberslnay be directed upward when the mechanism is set in the upright position for work. The plunger is tubular and interiorly' screw threaded and receives screw, C. The lower end of said screw rests in a bearing, A in the lower portion of the base, A. Immediately above said bearing, the screw is surrounded by a bevel gear wheel, C having'itsteeth directed upward and which is keyed to the screw. By turning said bevel gear. wheel in the proper direction, the screw is made to drive the plunger upward.

At its front, the base, A, has an opening towhich is secured a wall 'section,'A-, by means of four bolts, A In said wall section is a hearing. A*, which is horizontal and perpendicular to the axis of the screw.

In said bearing is a rotary shaft, C having its ends projecting through said hearing. The inner end of said shaft supports a bevel gear wheel, G which is rigid on said shaft.

The rotation of said shaft causes the rotation of the bevel gear wheel, C and the screw, 0.

To prevent the plunger from turning, it is provided on its exterior with an upright channel, B which receives a key, A having a shank, A, extending horizontally outward through the wall of the base, A, and receiving a nut, A

On the outer end of the shaft, C", is applied the ratchet mechanism, D, whereby said shaft is turned. Said mechanism comprises a group of'members which will be next described.

A body, D surrounds the shaft, C and may rock or rotate on said shaft'in a plane which is uprightand to which said shaft is pe pendicular. Said body has a socket approximately perpendicular to the shaft, C and adapted to receive a hand lever, D Said body has a chamber extending up ward and downward through the body and adapted to receive a ratchet wheel, D The portion of said shaft within said wheel is polygonal in order that said shaft and said wheel may rotate in unison while, as above stated, the body, D is free to reel: or rotate on the shaft, C excepting when engagement between said body and said wheel is made by means of the pawl, D

Said pawl is an upright member located within the body, D, at the right of the ratchet wheel and re'ciprocable upward and downward, perpendicularly to the hand lever, D and adapted to be heldateither of two elevations by a yielding tooth, D, seated in a horizontal barrel, D and surrounded by an expanding coiled spring, D bearing against the inner end of said barrel and against a shoulder, D", on said tooth and normally holding said. tooth at its outer limit and in one or the other of two notches, D, in the rear face of the pawl.

It will be observed that the path of reciprocation of the pawl, D is approximately tangential to the ratchet wheel, D and that any part of said pawl which approaches the line which is the axial line of the hand lever and cuts the axis of the ratchet wheel must at the same time approach said wheel, and, conversely, any part of said pawl which is moved away from said axial line must move away from said wheel. On the pawl are two jaw faces directed toward the ratchet wheel, one being above said axial line on the middle horizontal line of the ratchet wheel, and the other of said jaw faces being below said line. The upper of said jaw faces is provided with teeth, D, similar to the teeth on the jaws of a pipe wrench. The lower of said jaw faces has similar teeth, D Both of'said jaw faces are inclined, the upper part of the jaw face and the lower part of the lower jaw face being extended toward an upright line cutting the axis of the: ratchet wheel. Thus the naeaeoe portions of said pawl bearing said jaw faces are wedge-form, and when, the pawl 1s moved upward relative to the body, D

the upper jaw face moves away from the ratchet wheel while the lower jaw face moves toward the ratchet wheel; and when the pawl is moved downward relative to the body, D the lower jaw face moves away from the ratchet wheel and the upper jaw face moves toward the ratchet wheel. .Vhen the pawl is in its lower position, the yielding tooth, D, being then in the upper notch, D, the upper jaw face rests in engage-V ment with the ratchet wheel, the lower jaw face being entirely away from said wheel. The particular elevationof the pawl is determined by the yielding tooth, D. i hen strain is applied tending to move the pawl endwise, one of the oblique faces of the notch, D presses against the tooth, D, and tends to force the latter upward into the barrel, D against the resistance of the coiled spring, D W hen the pawl is in its lower position, the tooth, D, being in the upper notch, D and the hand lever, D is pressed downward, the portion of the body, D at theopposite side of the ratchet wheel axis will rise and lift the pawl, the latter slipping on the ratchet wheel. when the hand lever is lifted, the opposite end of the body, D is moved downward, and theportion ofthe pawl bearing the upper jaw face is wedged or jammed between the ratchet wheel and the opposite wall of the body, D such engagement being thus made by the pawl and the ratchet wheel as will compel the partial rotation of said wheel in unison with the'downward movement of the pawl. When the pawl is in its upper position, the tooth, D, being in the lower notch, D the above-described actions of the pawl relative to the ratchet wheel are reversed, the'pawl becoming wedged or jammed during upward movement of the adjacent end of the body, D

On the upper end of the pawl is an arm, D, which extends to the right along the rear of the body, I), and above the hearing, A". Since the pawlris in its lower position when i t is to make engagement for turning the shaft, for driving the plunger upward. the ratchet mechanism can be reversed by pushing said arm, D upward, sufficiently to disengage the teeth. D, of

the pawl from the ratchet wheel, D, when 7 said bony, D, turns in either direction, the tooth, D, remaining in the upper notch, D

Surrounding the portion of the bearing, 9U, between the body, D and the wall section, A}, is a sleeve, E, which is slidable endwise on said bearing. The rear end ofsaid sleeve normally bears against the wall section, A The front end of said sleeve is cut slanting to form an annular cam face, E bearing a ainst a cam face, D, on the arm,

D ofthexpawhnvhen said arm isyiflxits lower position. At opposite sides o ,the bearing, A the sleeve, E, has astud, E projecting rearward from the rear face of said sleeve loosely through the wall section, A to a cam face, E on a cam ring, E surrounding the bearing, A between the wall section, A andthe gear wheel, said ring being rotatable on said bearing and held against forward or rearward movement by said wall sectionand said, wheel, C Each of said cam faces, is so positioned asto normally receivethe adjacent stud, E against the innermost portion of said cam face, so that when said cam ring is partially rotated contra-clockwise, the cam faces, Eflwill force said studs, E outward, whereby the sleeve, F is forced outward and the cam face, E forces the arm, D up vard with sufficient force to carry the pawl upward far enough to disengage the teeth, I), from the ratchet wheel so that the latter will turn freely in either direction, the yielding teeth, D", retreating a little while the pawl is, thus raised.

The cam ring, E is connected with the pllunger by means of the connecting bar, which is arranged to be lltted by the plunger while the latter is moving into its upper limit. In itsouter face, the plunger has an upright channel, B to receive the body of the connectinglbar. The lower: end of the connecting rod is turned horizontally and has a fork, E, which receives a stud, E projecting outward radially from the .cam ring, so that when the connecting bar,

E is moved upward or, downward said stud, E is correspondingly moved upward or downward and the camring, is correspondingly partially turned. The inner face of the upright portion of theeonnecting bar has an uprightchannel, E terminating a little below the upper end offs'aid: bar and receiving a stud, B Fig. 7), locatedi'n the channel, B of the plunger. The parts are so proportioned as to bring the upper end of the bar, into the upper end of the channel, D whe'n'ithe plunger andfsaid bar and the stud, E on the cam r1ng are n their lowest or restpositions; and the stud, B is so positioned in the channel, 13 as to make enga gementin the upper end of the channel, E a little before the plunger reaches its upper limit, whereby the connecting bar is lifted suliiciently to lift the stud, E, and

turn the cam ring, E sufficiently ,to drive the sleeve, E, outward and cause the cam face, E on said sleeve to force the .arm, E and the pawl,D upward far enough to disengage the teeth, D of the pawl from the ratchet wheel.

The ratchet mechanism is now out of action and must so remain until the pawl, D has been forced farther upward into its upper working position. For accomplishing described.

this, the operator applies force to the pawl,

VD", sufficient to compel the yielding posiend of the connecting bar, E is engaged 1n the upper end of the slot, B whereby said bar is driven downward to its lower or rest position, During such movement, the fork, E, movesthe stud, E downward into the lower or rest position, whereby the cam ring is partially turned and space is made for the inward movement of the studs, E and the sleeve, E, to the position of rest. To limit the downward movement of the ,connecting bar, a stop A is extended inward from the wall of the base, A, into the path of the horizontalportion of the connecting bar at the proper elevation to support said bar when the latter has moved downward that, far., l-Vhen the plunger hasbeen lowered to its limit, the operator again reverses the ratchet mechanism by forcing the pawl downward into its lower position. Then said mechanism can be worked for turning the screw to again raise the plunger. A I hen thecam ring has been turned backward to its rest or normal position, the sleeve, E, may be moved inward to its normal position bythe hand of the operatorv or by the pressure ofthe arm, D of the pawl, D against the cam face, E on the sleeve, or suchmovement may be effected by the action of a spring, A, secured by one end by a screw, A to the outer face of the base, A, and hearing by its free end against an annular flange, E, located on the inner end ofthe sleeve.

I claim as my invention,

g 1. In a lifting. jack, the combination of a base, a plunger, a screw parallel'to. the plunger for relatively lifting the plunger, a gear wheel on said screw, a second gear wheel in constant engagement with thefirst gear wheel for transmitting motion to the latter, means for rotating the second gear wheel, a member movable in a path parallel to the path of the. plunger and in operative relation with'the latter to be moved in said path when the plunger moves to its upper limit, and means placing said movable memher into operative relation with said. rotatmeans for automatically putting said means out of action during the upward movement of the plunger, substantially as 2'. In a lifting jack, the combination of a base, a plunger, having an upright channel, a screw parallel to the plunger for relatively lifting the plunger, agear wheelon said screw, a second gear wheel in constant en agement with the first gear wheel for transmitting motion tothe latter, means for rotating the second gear wheel, a member movable endwise in said channel and in operative relation with said plunger to be moved in said channel 'when the plunger moves to its upper limit, and means placing said movable member into operative rela tion with said rotating means for automatically'putting said means out of action during the upward movement of the plunger, substantially as described. a

'3. Ina lifting jack, the combination of a base, a plunger, a screw parallel to the plunger for relatively lifting the plunger, a gear wheel on said screw, a shaft adjacent said screw, a second gear wheel on said shaft and in constant engagement with the first gear wheel, means for rotating said shaft, a member movable in a path parallel to the path of the plunger and in operative relation with the latter to be moved in said path,

when the plunger moves to its upper limit and means placing said movable member into operative relation with said rotating means for automatically putting said means out of action during the upward movement of the plunger, substantially as described.

4. In a lifting jack, the combination of a base, a plunger, a screw parallel to the plun ger for relatively lifting the plunger, a bevel gear wheel on said screw, a rotary shaft perpendicular to said screw, a bevel gear wheel located on said rotary shaftand in constant engagement with the other bevel gear wheel, driving means for rotating said rotary shaft, a member movable in a path parallel to the path of the plunger and in operative relation with the latter to be moved in said path when the plunger moves to its upper limit, and means placing said movable member into operative relation with said driving means for automatically putting said driving means out of action during the upward movement of the plunger, substantially as described.

5. In a lifting jack, the combination of a base, a plunger having an upright channel, mechanism for relatively lifting said plunger, said mechanism comprising a rotary shaft perpendicular to said plunger and a pair of gears in continuous engagement with each other, one of said gears being on said shaft, means for turning said shaft, a member movable in said channel and in opera tive relation with said plunger to be moved in said channel vwhen the plunger moves to its upper limit, a sleeve concentric and slidable parallel to said shaft, means operatively connecting saidsleeve and said member which is movable parallel to the movement of said plunger, and means for placing said sleeve in operative relation with said shaft-turning means for automatically )uttin said turnin means out of action during the upward movement of the plunger, substantially as described.

6. In a'lifting jack, the combination of a base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising a rotary shaft perpendicular to said plunger and a pair of gear wheels in continuous engagement with each other and one being mounted on said shaft, means for I turning said shaft, a connecting member adjacent the plunger, means on said plunger for engaging said member and moving it in unison with the plunger when the latter approaches its upper limit, a sleeve concentric to and slidable parallel to said shaft,

plunger and means for rotating said shaft, 1

a sleeve concentric with and slidable parallel to said shaft, means operable by the endwise movement of said sleeve for placing said shaft-turning meansout of action, a cam ring also'concentric to said rotary shaft and in operative relation with said sleevefor moving the latter endwise by the partial rotation of said ring, and means operatively connecting said ring and the plunger for partially rotating the ring when the plunger approaches its upper limit, substantially as described.

8. In a lifting jack, the combination of a base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising a rotary shaft perpendicular to said plunger and means for rotating said shaft, a sleeve concentric with and slidable parallel to said shaft, means operable by the endwise movement of said sleeve for placing said shaft-turning means out of action, acam ring also concentric to said rotary shaft'and in operative relation with said sleeve for moving the latter endwise by the partial rotation of said ring, a spring for returning said sleeve to normal or rest position, and

means operatively connecting said ring and the plunger for partially rotating the ring when the plunger approaches its upper limit, substantially as described.

, 9. In a lifting jack, the combination of a hollow base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising'a rotaryshaft perpendicular to said plunger and means for rotating said shaft, a sleeve located outside the wall of the bass and consentric with and slidable I parallel to said shaft, means operable by the endwise movement of said sleeve for placing said shaft-turning means out of action, a

cam ring at the inner side of said wall and also concentric to said rotary shaft and in operative relation with said sleeve for moving the latter endwise by the partial rotation of said ring, and means operatively connecting said ring and the plunger for partially rotating the ring when the plunger approaches its upper limit, substantially as described.

10. In a lifting jack, the combination of a base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising a rotary shaft perpendicular to said plunger and means for rotating said shaft, a cam ring concentric to said shaft, a member movable in a path parallel to the path of said plunger and in operative relation with said cam ring for turning the latter when the plunger approaches its upper limit, and means operatively relating the cam ring and the shaft-turning means for placing the latter out of action, substantially as described.

11. In a lifting jack, the combination of a base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising a rotary shaft perpendicular to said plunger and means for rotating said shaft, a cam ring concentric to said shaft and bearing a stud, a member movable in a pat-h parallel to the path of the plunger and in Copies of this patent may be obtained for five cents each, by addressing the operative relation with said stud for turning said cam ring when the plunger approaches its upper limit and means operatively relating the cam ring and the shaft-turning means for placing the latter out of action, substantially as described.

12. In a lifting jack, the combination of a base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising a ratchet wheel and a pawl for engaging said ratchet wheel, and means in 0perative relation with said pawl and said plunger for transmitting motion from the plunger to said pawl for releasing the latter from the ratchet wheel when the plunger approaches its upper limit, substantially as described.

13. In a lifting jack, the combination of a base, a plunger, mechanism for relatively lifting said plunger, said mechanism comprising a ratchet wheel and a pawl movable in a path approximately tangential to said wheel, and means in operative relation with said pawl and said plunger for transmitting motion from the plunger to said pawl for the disengagement of the latter from the ratchet wheel when the plunger approaches its upper limit, substantially as described.

In testimony whereof I have signed my name, in presence of two witnesses, this 4th day of April, in the year one thousand nine hundred and sixteen.

LOCKE ATIVELL.

Commissioner of Patents,

Washington, D. G. 

